I haven't paid much attention to carbonation up until recently, because my method hasn't changed in the three years I've brewed, and it's perfectly acceptable to me. My friend says that every homebrew he tastes, which is entirely from myself and the three other brewers in our club, seems "over carbonated".

After much discussion, he agrees that he thinks this may be related to the size of the bubbles in the beer. I took one of my beers that had been sitting in the fridge for far longer than most, and noticed that although it was starting to decrease in quality, the carbonation bubbles were quite small.

Everything I look up is either super detailed chemist stuff that is hard for me to understand, let alone apply, or what appears to be people making stuff up based on one or two experiences. Does anyone know the effect of age, temperature, or anything else on carbonation bubble size?

3 Answers
3

In an experiment I did years back, I found that the amount of time you give the CO2 to go into solution is the main factor. The reason that DME seems to give finer bubbles is because of the amount of time it takes to ferment out, which gives the CO2 more time to dissolve. DME, though, is not a good sugar to use for priming because the fermentability of it varies from one type and manufacturer to another. Therefore, you never know exactly how much fermentable sugar you're adding to a batch. Keeping the beer cold once the sugar has fermented out will increase the solubility and give you finer bubbles.

I think some of it too related to time and clarification. There are a lot of super fine particles that don't really contribute to a noticable haze, but they do act as nucleation sites. As a beer sits in the bottle those things settle out, and the bubbles tend to form on smaller and smaller particles making finer bubbles.
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brewchezMar 1 '11 at 13:00

Temperature, FG of the beer (density), the amount of CO2 dissolved in the beer, and nucleation sites (in this case, your friend's tongue) would be the technical factors in play regarding bubble size. Worrying about bubble size is a bit silly though. When I carbonate a beer, I force carb it to taste based on the beer I'm making. If you're bottle conditioning, simply use less or more priming sugar to adjust your carbonation. You aren't going to be able to change the size of bubbles, just the amount of carbonation.

This pretty well-read (and debated and disagreed with) study suggests that using DME instead of corn sugar will yield a tighter head (smaller, more densely-packed bubbles). hbd.org/atommash/bennett/dmevscs.txt Anecdotally, I've found this to be somewhat true in the three or four batches I primed with DME. My "study" was not scientific in any way, though, and I now prime with simple table sugar.
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JackSmithFeb 28 '11 at 15:20

I (think) alcohol content may play a role as well. With liquor you can visibly determine proof by observing the size of bubbles and their rate of dissipation--so I would presume alcohol would have an effect in beer as well.
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STWFeb 28 '11 at 16:13